There are some sights around the planet that can take your breath away. From unexplainable huge rocky structures to magnificent waterfalls, the Earth has countless wonders. One of these is, without doubt, the Northern Lights also known as the Aurora borealis. This amazing display of color and lights in the sky can be seen from different parts of the world and at different times. This natural magical display can be explained by the behavior of particles in the Earth’s atmosphere.
Seeing the Northern Lights
The Northern Lights are a sight like no other. They appear as a dazzling display of colors in the sky. Different hues can be seen including greens and pinks, as well as various shades of yellow, red, blues, and violets. The display can appear as arcs, patches, scattered clouds of light, or even rippling curtains and shooting light rays. This lights up the sky in a way that cannot be seen anywhere else.
The display can actually be seen both in the northern hemisphere where it is known as Aurora borealis and in the southern hemisphere where it is known as Aurora australis. The best places to get the best view include areas closer to the North and South Poles. Parts of Canada, Alaska, Greenland, Iceland, Norway, and Siberia in the north and around Antarctica and the southern Indian Ocean in the south are the main viewing locations. Most of the time, what can be seen in the north and in the south are mirror-images in terms of shape, color, and timing.
As for the time and season, the display is visible during the winter at night. Clear nights are the best, and around midnight is a recommended time. The auroral activity happens on a cyclic basis that peaks every roughly 11 years.
What Causes This Phenomenon?
The bright display of dancing light comes from the collisions of electrically charged particles from the sun’s atmosphere and gaseous particles in the earth’s atmosphere. Depending on the gas involved, the display may take on a different one of the colors mentioned above.
The Earth’s atmosphere is made up of 78 percent of nitrogen gas, 21 percent of oxygen gas, and much lower volumes of gases such as argon and carbon dioxide. Oxygen molecules are responsible for a pale yellowish-green color, which is the most common color in the aurora. This happened at the height of about 60 miles above the earth’s surface. When oxygen at a much higher altitude of around 200 miles is involved, the auroras come off as all-red. When the atmospheric gas is nitrogen, the auroral display produces a blue or purplish-red color. In general, the lights can extend above the Earth’s surface from 50 miles to as high as 400 miles.
The atmospheric gases collide with charged particles from the sun, which are free electrons and protons. These particles usually exist within the atom, but because the temperatures at the sun are extremely hot in the millions of degrees Celsius, collisions taking place there are very explosive.
As the sun rotates, the subatomic particles are thrown from the sun’s atmosphere, pass through gaps in the magnetic field, and end up in the earth’s atmosphere. This happens when they are blown there by the solar wind. The solar wind is a stream of charged particles, which are mainly protons and electrons, flowing from the sun through the solar system. It travels at a great speed of 900 km/s and has a temperature of 1 million degrees Celsius.
The charged particles from the sun that enter the Earth’s atmosphere are only able to do so near the north and south poles. This is because the Earth’s magnetic field is weaker at those points, so it cannot deflect the particles quite as well.
Alexandra grew up dreaming of being a great science explorer. She always wanted to travel the world and explore some of the greatest science mysteries of the times. After high school, she studied chemistry in college and spent most of her summers working on research projects alongside her professors. It was there that Alexandra got clarity about what she wanted to do in the future. She now works full time in science research at a teaching university and is planning to go to medical school in a few years. She likes to stay up-to-date with the latest discoveries in science and share her love for science through her writing.